Process of manufacturing iron electrodes for use in alkaline accumulator.



H Unrrnn s ra rns earner ca ries.

AXEIJ THEODOR KONSTANTIN ESTELLE, 0F FLISERYID, SNEDEN, ASSIGNOR TO NYA ACKUHULA'IOR AKTIEBOLAGET JUNGNER, OF FLISERYD, SXVEDEN.

rnoonss or manur'eczqnnme teen nnuctrnonns son use In ALKALIHE eccununarroas.

983,430.; Specification teteemrmm. m m a, you Ho meme;

for Use in Alkaline Accumulators; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to'which it appertains to make and use the same.

The manufacture of an iron mass suitable as active material in negative electrodes of alkaline accumulators has hither-w been connected with some difliculties on account of the tendency of the iron to oxidize in the air and also on account of the high oxygen compounds of this meta] being scarcely reducible. A ce dition for the greatest possible conductivity is that the metal used is in a chemically finely divided state, when the electrode is fully prepared or charged. As" iron, however, in that state is pyrophorie,'1t cannot directly be used for the purpose indicated.

I have discovered tha if iron is clos trol tically preci itated from a. salt solution in t e presence 0 a solution of certain other metals, a spongy alloy in finely divided state of iron and the other metal will be formed, which alloy possesses special properties and can be advantageously used as active material in negative electrodes. The additional metal used may be one which is in- 'soluble 'by anode-electrolysis in alkaline solutions.

cadmium may be mentioned.

I prepare an lron-cadmiumelectrode the following wayzl take a concentrated solution'of ferrous sulfate and mix the same with a solution of cadmium sulfate and I introduce this mixture in an electrolyzing apparatus. .The proportions may be such as to correspond tothe composition of the metal alloy desired. For the anodes, plates of iron and cadmium may be used, said plates being so adapted that the effective surfacesare in direct ratio to the propertions of the metals of the alloy but -iuverse ratio to. the atomic weight f the As an example of such a metal Application filed name s, mic. semi No. sauces.

' metals. If, for instance, the alloy is to contain two parts of iron and one part of cadmium, the efiective anode surface of the iron, seeing that the atomic weight of the ferrous iron is only a half of that of cadinium, may be four times as great as that of the cadmium. For the cathode, plates of iron or cadmium are suitably used, the current density being about 10 amperes per square deciineter. The precipitated alloy is further washed, pressed to cakes in a hydraulic press and dried at a temperature of'50 to C. The alloy is then ground into a coarse owder, formed into bricks and introduce in perforated sheetmetal pockets. After having been subjected to cathode electrolysis for reduction of the small quantities of oxid formed during the Washing and drying; processes, the electrode is then ready for use. Each. grain of the coarse powder thus produced represents a conglomerate of very Jhnemetallic parts,

and the cadmium particles are in a sufii ciently subdivided state to act as active lTitl" terial. But as soon as this action takes place, the iron particles disengage from the alloy as very finely divided particles, which possess a high degree of activity.

With an alloy containing 56.5 per cent. oi cadmium and 43.51am cent. of iron i have obtained e capacity of l ampere hour for each 3.5% grams of the alloy, come spending to 82.3 per cent. or the greatest 1w obtainable capacity.

As Will be understood, the active inatcriei produced according to the method described above Will be in a metallic state, thus having a high Weight per unit ofv volume, the consequence being that a relatively great quantity of the same may be introduced in an electrode of determined space.

1 claim 1. A. process for manufacturing; an electrically active iron mass for negative elec trodes of alkaline accumulators, which consists in subjecting a solution of an iron salt to electrolysis in the presence of a solution of another metal insoluble in alkaline solu tions.

2. A process for inanufacturing'an electrically active iron mass for negative electrodes of alkaline accumulators, which con-- precipitntetlviron." I J 3. A process forinenufacturing on eleesisis in subjecting a. solution or? an iron salt to electrolysis in the rresence etgs solution of another rnetnlinsoluble in zilkaline'solulions and forming a spongy alloy With the trically active iron-amiss for negative electrodes oi alkaline eccumulators, which con sists in subjecting a solution of ferrous-sill fate to electrolysis in the presence of a solution of anothermetal insoluble in alkaline soli'itions and forming spongy alloy wlth the precipitated iron.

l. A. process for manufacturing an electricsllyuctivc iron mass fornegative elec' trodes of alkaline accumulators, which consists in subjecting a solution of an iron salt to'electrolysis in the presence of a solution of a cadmium salt.

ii. A process for manufacturing an. electrically active iron mass for negative electrodes of alkaline accumulators,'Which' consists in subjecting a solution of ferroussnltst'e to electrolysis in the presence of a sol ulion oi a ceclmiuin salt. v i

6. A process for manufacturing an electrically active iron mass for negative electrodes oi slimline accumulators, which conin subjecting a solution. ofterrous sulf fate to electrolysis in the presence of a solution of cadmium sulfate.

'7. A process for manufacturing an electricallynctive lron mass for ncgatn'o electrodes of alkaline accumulators, which consists in subjecting a solution of an iron saltto electrolysis in the presence cfla solution of another metal insoluble in alkaline solu tions,'washingthe precipitated alloy, pressing and drying the same, molding the dry product to a powder and compressing said powder into bricks.

8. A process of manufacturing an electrically active iron mass for negative electrodes of alkaline accumulators, which consisls in subjecting a solution of ferrous-sulfate to electrolysis in the presence of a solution of cadmium-sulfate, Washing the precipitated iron-cadmium alloy, pressing and 

